Collapsible carton and blank for forming it



R. E. PAIGE COLLAPSIBLE CARTON AND BLANK FOR FORMING IT Filed Jan. 14, 1969 March 17, 1970 2 Sheets-Sheet 1 Af/omeys March 17, 1970 R. E. mGE 3,50 ,08

COLLAPSIBLE CARTON AND BLANK FOR FORMING IT Filed Jan. 14, 1969 2 SPeets-Sheet 2 INVENTOR. Richard E. Paige By DowlgHoxAe, Fo/fhfull 8 Hapgood Attorneys United States Patent Oflice Patented Mar. 17, 1970 3,501,081 COLLAPSIBLE CARTON AND BLANK FOR FORMING IT Richard E. Paige, New York, N.Y., assignor to The Paige Company Containers, Inc., New York, N.Y., a corporation of New York Filed Jan. 14, 1969, Ser. No. 791,081 Int. Cl. B65d /36 US. Cl. 229-39 14 Claims ABSTRACT OF THE DISCLOSURE A collapsible carton, formed from a unitary blank having a smooth bottom comprising a first flap attached to aside wall and coextensive with the carton bottom, two generally triangular flaps attached to opposite sides of the first flap and to the adjacent end walls and a fourth flap attached to the remaining side wall. The triangular flaps fold upon themselves and trap the fourth flap therebetween providing a reinforced, completely supported, smooth bottom structure. A plurality of parallel fold lines are provided at specific locations to accommodate the several layers of material which overlie one an other due to the structure of the carton.

This invention relates to collapsible cartons and, more particularly, to open tray type cartons having a smooth interior bottom surface.

Collapsible cartons are used in great numbers today for many different purposes including storage, toting, display, etc. It is desirable for the cartons to be able to be easily set up with a minimum of effort, skill and dexterity, and to be able to be easily knocked down after use for storage purposes. Since many of these cartons are not used continuously and, due to their expense, are not readily disposable, it is desirable to have a carton which can be easily collapsed into a flat position. This will permit stacking of large numbers of such cartons in order to conserve storage space. It is also desirable to provide a carton with a smooth interior, especially a smooth bottom surface. Since these cartons are often used to carry heavy loads it is also desirable to have a reinforced bottom construction with a single side wall, thus saving the cost of excess materials employed in double wall cartons while providing a reinforced bottom wall.

The improved carton is formed from a unitary blank having rectangularly shaped side walls and end walls defined by fold lines. The bottom is formed by four interacting flaps including a primary bottom flap attached to the lower edge of a side wall positioned on the unfolded blank between two end walls. The primary bottom flap has dimensions coextensive with the bottom of the carton when it is set up. A pair of generally triangular flaps are hingedly attached along the side edges of the primary bottom flap and along the lower edge of the end walls adjoining the primary bottom flap. A secondary bottom flap is hingedly attached along the lower edge of the re maining side wall. The width of the secondary bottom flap is less than the width of the primary bottom flap.

In pre-assembling the box at the factory the flaps forming the bottom of the box are folded upwardly against the inner surfaces of their respective side and end walls. The side and end walls are then folded into a rectangu lar shell and attached together by conventional means such as a glue flap. To set up the box the primary bottom flap is forced downwardly toward the bottom of the box which causes the generally triangular flaps at the sides of the primary bottom flap to fold upon themselves. The secondary bottom flap is trapped between the portions of the generally triangular flaps folding upon themselves, locking the secondary flap in place. The secondary bottom flap and the triangular flaps provide reinforced support for the edges of the primary bottom flap which are not integrally connected to the side wall. The primary bottom flap, forming the interior surface of the carton and being coextensive with the bottom of the carton, .provides a smooth interior bottom surface.

This invention will be better understood from the detailed description below taken together with the drawing in which,

FIGURE 1 is a front view of a blank formed in accordance with this invention,

FIGURE 2 is a perspective view having cut-away portions showing a carton formed from the blank of FIG- URE 1 in its initial step in its erection,

FIGURE 3 is a plan view illustrating the carton in a partially collapsed position,

FIGURE 4 is a perspective view having cut-away portions showing the carton during an intermediate step in its erection,

FIGURE 5 is a plan view looking into a carton, formed of corrugated board, when the carton is set up, and

FIGURE 6 is a perspective view showing the under side of a set up carton formed from the blank of FIG- URE 1.

With reference to the drawing and, more particularly, FIGURES 1 and 2, there is illustrated a unitary blank 10 cut from sheet material such as cardboard, solid fiber, paperboard, or other suitable foldable sheet material. The blank 10 includes four wall panels 12, 14, 1'6, 18, two of which (12, 16) will be called end Wall panels and two of which (14, 18) will be called side wall panels for con venience in discussion. The end and side wall panels are arranged in alternating fashion and are defined by triple transverse fold lines 20, 22, and double transverse fold lines 24. A connecting flap 26 is provided at one end of the blank '10 connected to one of the walls 18 by double fold lines 28. The explanation for the use of the triple and double fold lines is explained in detail below but, the reason is basically to accommodate the folding and interrelationship between the several overlying layers of material. Folding the blank 10 along the transverse fold lines causes the four walls, 12, 14, 16, 18, to form a rectangular tubular structure as may be seen in FIGURE 2. In order to join the exterior blank walls 12, 18 the connecting flap 26 is attached to the wall 12 adjacent to the connecting flap 26 when the rectangular tubular structure is formed. The attachment of the connecting flap 26 to the adjacent wall 12 may be by any conventional means such as glue or staples.

The bottom structure for the carton formed from the blank 10 is formed from a plurality of flaps all of which are attached to the bottom longitudinal edge defined by a pair of fold lines 30, of the walls 12, 14, 16, 18. The bottom structure includes a primary flap 32 joined to the bottom edge of the side wall 14 which is located between the two end walls 12, 16 when the blank 10 is in its unfolded position, as illustarted in FIGURE 1. The longitudinal dimension of the primary flap 32 is equal to the longitudinal dimension of the side wall 14 or, in other words, the primary flap 32 extends between the fold lines 20, 22 which define the length of the side wall 14. The transverse dimension of the primary flap 32 is substantially equal to the longitudinal dimension of the end Wall 16. In other words, the distance between the fold line 30 along which the primary flap 32 is connected to the side wall 14 and the exterior edge 36 of the primary flap 32 is equal to the distance between the fold lines 22, 24 defining the length of the end wall 16. Since the carton is rectangular the transverse dimesion of the end wall 12 is equal to that of the end wall 16. Because of these dimensions the surface area of the primary flap 32 is coextensive with an 3 area defined by the four walls 12, 14, 16, 18 when set up into the rectangular shell.

The primary flap 32 also includes as an integral part thereof two generally triangular flaps 38, 40 defined by the longitudinal lower edge 30 of the walls and a pair of double transverse fold lines 42, 44. As can be seen in FIGURE 1 these triangular flaps 38, 40 span between the primary flap 32 and the end walls 12, 16. Each triangular flap is provided with a double fold line 45 which extends from the intersection of the primary flap 32 and the corresponding end wall to the exposed edge or hypotenuse 46, 47 of the triangular flaps 38, 40 respectively.

There is also provided a secondary bottom flap 48 hingedly attached to the bottom edge of the remaining side wall 18. The secondary flap 48 is equal in length to the side wall 18 to which it is attached. A transverse dimension of the secondary flap 48 or, in other words, the distance between the bottom edge 30 of the walls and the exposed edge 50 of the secondary flap is less than the corresponding dimension of the primary flap 32. It is preferred to have the transverse dimension of the secondary flap 48 a little greater than one-half the transverse dimension of the primary flap 32. In order to provide a proper interlocking relationship between the secondary flap 48 and the triangular flaps 38, 40, as described below, the transverse dimension of the secondary flap 48 must be equal to or less than the distance from the interior edge 52 of the secondary flap to the point of intersection of the fold lines 45 and the triangular fiaps hypotenuse 47, this distance being represented by the dimension line 54.

The carton is pre-assembled at the factory as follows: the primary flap 32, including the generally triangular flaps 38, 40 and the secondary flap 48 are folded upwardly along the fold lines 30 defining the bottom edge of the Walls 12, 14, 16, 18 so that each of these flaps lie adjacent to what becomes the inner surface of each of the walls to which they are hingedly attached. The blank is folded along the transverse fold lines 20, 22, 28 to define the walls 12, 14, 16, 18 and the connecting flap 26 and to form a rectangular shell with the bottom forming flaps contained within the shell, as is shown in FIGURE 2. The connecting flap 26 is then joined to the adjacent end wall 12 such as by gluing. For storage and shipping purposes the shell may be collapsed by pressing inwardly on,

two opposite corners, for example corners 56, 58 illustrated in FIGURE 2, until the corners become contiguous forming the flat structure illustrated in FIG- URE 3.

It is preferred that the shell be collapsed with the corners 56, 58 being contiguous, the corner 58 being formed partially by the connecting flap 26.

As can be seen in FIGURE 3, when the carton is c'ollapsed one of the remote corners, corner 60 has several layers of material in overlapping relationship. FIGURE 3 illustrates the carton partially collapsed to show the various layers clearly. Since the sheet material used usually is relatively heavy, for example about Vs"; three parallel fold lines 20 are provided to form a wide separation between the parallel side and end walls 14, 12 in order to accommodate the overlapping layers. While the corner 56 does not require the same degree of separation because, when collapsed properly, it is not folded on itself, it is provided with the same number of fold lines 22 in the event the carton is folded with the corners 60, 62 being contiguous.

When it is desired to set the carton up for use one merely presses on the remote corners 60, 62 causing the shell to obtain its rectangular tubular configuration. The secondary flap 48 is folded partially downwardly and then the primary flap 32 is pressed downwardly. As the primary flap 32 moves downwardly, the generally triangular flaps 38, 40 fold upon themselves along the fold lines 42 trapping the secondary flap 48 between the two portions of the triangular flaps 38, 40. This may be clearly seen by comparing the progressive steps illustrated in FIGURES 2 and 4. Continued movement of the primary flap 32 downwardly locks the secondary fiap in place. The primary fiap forming the inner surface of the carto and being coextensive with the bottom surface area of the carton completely covers the bottom of the cartor and presents a smooth interior surface as may be seen in FIGURE 5. Furthermore, because the transverse dimension of the primary fiap 32 is substantially equal to the longitudinal dimension of the end walls 12, 16 the primary flap is retained in the bottom forming position by the binding force or friction between the exterior edge 36 of the primary flap and the side wall 18. FIGURE 6 illustrates the exterior appearance of the bottom of the carton showing the interlocking relationship of the bottom structure. FIGURES 2, 4, and 5 illustrate the reinforcing feature of the structure wherein the three edges of the primary flap 32 which are not integrally connected to the walls of the carton are supported by members which are integrally attached to and hinged to the carton body. For example, the transverse edges of the primary flap 32 defined by the fold lines 42, 44 are supported by the double thickness formed by the triangular flaps 38, 40 folding upon themselves which are integrally connected to the end walls 12, 16. The exterior edge 36 is supported by the secondary flap 48 which is integrally attached to the bottom of the front side wall 18.

FIGURES 4 and 6 illustrate the need for the double fold lines 45 dividing the triangular flaps 38, 40 into two parts. More particularly, since the secondary flap 48 lies between the two parts of the triangular flaps 38, 40, the double fold lines 45 provide sufficient spacing to accommodate the secondary flap.

In addition to the number of fold lines utilized being important for reasonably thick or heavy sheet material, the location also is of importance as is illustrated in FIG- URE 5. Due to the connecting flap 26 being on the inside of the carton it is desirable to provide a clearance between the end wall 12 and adjacent edge 63 of the primary flap 32. Such a clearance allows the primary flap to be forced downwardly without interference from the connecting flap 26 and also accommodates the extra thickness resulting from the connecting flap. The clearance is provided by making the inner fold line 42a of the primary flap 32 colinear with the inner fold line 20a of the side wall 14 as may be seen in FIGURE 1. When the carton is set up the triple fold lines 20 between the side wall 14 and end wall 12 form a rounded corner 60 which spaces the end wall 12 from the edge 63 of the primary flap a distance equal to the thickness of the connecting flap 26.

To facilitate carrying the carton, hand holes 64, 66 are provided through the end walls 12, 16 respectively.

After the carton has been used and it is desired to collapse it for storage all that is necessary is for the user to press inwardly on the portion 67 of the primary flap 32 which is exposed to the under side of the carton (see FIGURE 4.). Movement of the primary flap inwardly toward the inner surface of the rear side wall 14 causes the general triangular flaps 38, 40 to unfold. The secondary flap 48 then is pushed upwardly toward the inner surface of the front side wall 18 and the carton is collapsed as described above, by pushing inwardly on the opposite corners 56, 58.

As can now be appreciated the carton formed in accordance with this invention is an open tray type having a smooth interior bottom. The carton is very easy to set up and collapse and requires a minimum of storage space. The bottom is strong by virtue of the reinforcements and supporting structure and requires no gluing, stapling, or taping.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A collapsible carton, formed from a unitary blank, comprising four walls and a bottom, the bottom including a first flap hinged along one edge to a first wall and extending across the carton toward a second wall opposite the first wall, a second flap hinged along one edge to the second wall and extending partially across the carton toward the first wall, third and fourth generally triangular flaps, each hingedly attached along one edge to opposite sides of the first flap and along another edge to the corresponding wall adjacent the sides of'the first flap, the third and fourth flaps having a fold line extending from the point of intersection of said one edge and said another edge to the third edge, the second flap being trapped between the portions of the third and fourth flaps on opposite sides of the fold line when the first flap is forced into its bottom forming position.

2. A collapsible carton as defined in claim l wherein the first flap is coextensive with the bottom of the carton.

3. A collapsible carton, formed from a unitary blank, comprising a front wall, a rear'wall, first and second side walls, and a bottom, the walls being joined together along hinge lines to form a rectangular structure, the bottom including a first fiap hingedly attached along one edge to the bottom of the rear wall and having a surface area coextensive with the bottom of the carton, a second flap hingedly attached along one edge to the bottom of the front wall and having a length measured from said one edge less than the width of each of the side walls, third and fourth flaps of generally triangular shape each having mutually perpendicular first and second edges, a third edge interconnecting the first and second edges and a fold line extending form the intersection of the first and second edges to the third edge, the first edge of the third and fourth flaps being hingedly attached to opposite sides of the first flap, the second edge of the third and fourth flaps being hingedly attached to the bottom of the first and second side walls respectively, each of the first, second, third and fourth flaps being folded upwardly and inwardly such that each of the flaps lie adjacent the inside surface of the wall to which they are attached whereby downward movement of the first flap causes the third and fourth flaps to fold upon themselves along their fold lines trapping the second flap therebetween and providing a reinforced smooth bottom.

4. A paperboard blank for forming a collapsible carton comprising in series relationship a first end Wall, a first side wall, a second end wall and a second side wall, the walls being separated by transverse fold lines, a first bottom flap hingedly attached along one longitudinal edge of the first side wall, a first generally triangular flap hingedly attached along one edge thereof to a transverse edge of the first flap and along another edge thereof to a longitudinal edge of the first end wall, a second generally triangular flap hingedly attached along one edge thereof to the other transverse edge of the first flap and along another edge thereof to a longitudinal edge of the second end wall, a diagonal fold line in each of the triangular flaps extending from the intersection of the first bottom flap and the end wall to an unattached edge of the triangular flap, a second bottom flap hingedly attached along one longitudinal edge of the second side wall and having a transverse dimension less than the longitudinal dimension of the end walls, and a connecting flap along the transverse outer edge of one of the walls.

5. A paperboard blank as defined in claim 4 wherein the first side wall and the first end wall are separated by at least two parallel, closely spaced fold lines.

6. A paperboard blank as defined in claim 4 including a second diagonal fold line parallel to and closely spaced from the diagonal fold line in each of the triangular flaps.

7. A paperboard blank as defined in claim 5 including a second diagonal fold line parallel to the diagonal fold line in each of the triangular flaps, the spacing between each pair of parallel fold lines is substantially equal to the thickness of the paperboard of which the blank is made.

8. A paperboard blank as defined in claim 7 where the connecting flap is attached to the second side wall.

9. A paperboard blank as defined in claim 4 wherein the first bottom flap has a transverse dimension substantially equal to the longitudinal dimension of the end walls.

10. A paperboard blank as defined in claim 8 wherein the first bottom flap has a transverse dimension substantially equal to the longitudinal dimension of the end wall.

11. A paperboard blank as defined in claim 9 wherein the transverse dimension of the second side wall is no greater than the distance, measured parallel to the longitudinal edge of the second side wall, from the transverse fold line between the second end wall and the second side wall to the intersection of the diagonal fold line and the unattached edge of the second generally triangular flap.

12. A paperboard blank as defined in claim 10 wherein the transverse dimension of the second side wall is no gretaer than the distance, measured parallel to the longitudinal edge of the second side wall, from the transverse fold line between the second end wall and the second side wall to the intersection of the diagonal fold line and the unattached edge of the second generally triangular flap.

13. A factory-assembled corrugated structure for forming a generally rectangular, open top carton comprising two side walls and two end walls and a connecting flap integrally attached on one edge thereof to one of the walls and fixedly attached to another one of the walls, a set of six flaps hingedly connected to the bottom edges of the walls, the set of flaps including a primary bottom flap hingedly connected to one side wall, two web-like flaps joining the bottom edges of the end walls with the side edges of the primary bottom flap and a secondary bottom flap hingedly connected to the bottom edge of the remaining side wall, the dimension of the secondary bottom flap, in a direction normal to the bottom edge to which it is connected, is smaller than the corresponding dimension of the primary bottom flap, the structure lying flat for shipping with each flap lying between the walls and adjacent to the inner surface of the wall to which it is connected whereby pushing the flaps downwardly effects formation of a rectangular, open top carton.

14. The structure defined in claim 13' wherein the side walls and end walls are hingedly attached to each other by at least two parallel fold lines enabling the structure to be collapsed into a relatively flat structure.

References Cited UNITED STATES PATENTS 2,348,378 5/1944 Goodyear 229-37 2,799,442 7/1957 Van Rosen 229-37 DAVID M. BOCKENEK, Primary Examiner U .8. Cl. X.R. 

